Process for recovery of sulphur dioxide from oils containing same



'May 13, 1930. I G. C'ATTANEO 5 5 PROCESS FOR RECOVERY OF SULPHUR DIOXIDE FROM OILS, CONTAINING 5H3 Filed llay- 2' 1926 ,1; V, the condenser Patented May 13, 1930 UNITED STATES PATENT OFFICE GIU'SEPPE CATT ANEO, OF HILVERSUM, NETHERLANDS, ASSIGNOR T ALLGEMEINE GESELLSCEAFT FUR GHEMISCHE INDUSTRIE M. 3. IL, OF IBERLIN-SCHbNEBERG,

GERMANY PROCESS FOB.IREGOVERY OF SULPHUR DIOXIDE FROM OILS CONTAINING SAME Application flied m 27, 1926, Serial No.

from the extract is eifected by evaporation in closed vessels, after which the sulphurous acid is liquefied ina condenser so that it can be used again. The heating required for evaporation is in most cases supplied by the exhaust steam from the steamengine used for driving the plant,'which may be insuflicient when very large quantities of sulphurous acid are involved.

The'object of the invention is to efiect a i; saving in the amount of heat to. be supplied by introducing high pressure evaporation.

In the accompanying drawing an arrangement for carrying out the process'is shown by way of example. The evaporators V and C, the compressor K, the pumps P and P and the pipes L and L operate in the usual manner. The new feature consists in the arrangement of one or more evaporators placed before the apparatus and working at a higher pressure than the condenser pressure, the two high pressure evaporators H and H being shown by way of example. The pressure in the high pressure evaporator H is greater than the pressure in the high pressure evaporator H and the pressure in the latter is greater than the pressure in the evaporator V By the pump P and the pipe L the solution of extract and sulphurous acid is fed to the first high pres- I sure evaporator H This evaporator is heated directly by a fire or indirectly by a system of pipes, into which for instance exhaust steam is supplied from the engine driving the apparatus, and the heat supply is regulated i in such a manner that the required highpressure and the correspondingly high temperature are obtained when evaporating the sulphurous acid from the solution. During this process the solution is freed from a portion of the sulphur dioxide and flows through a 112,136, and in Germany March 5, 1926.

pipe with a regulating valve R into the high pressure evaporator H which is at a lower pressure. Owing to the expansion which takes place the-temperature of the solution will drop, a corresponding proportion of the sulphur dioxide being evaporated. In the high pressure evaporator H is a system of pipes, the interior of which is connected to the vapour space of the high pressure evaporator H by a pipe. As the temperature of the solution in the high pressure evaporator I H is lower than the temperature of the sulphurous acid vapours in the high pressure evaporator H a liquefaction of the sulphur dioxide vapours coming from the high pressure evaporator H will take place in the system of pipes within the high pressure evaporator H the heat liberated during the liquefaction being transmitted to the solution in the high, pressureevaporator H and causing a corresponding evaporation of sulphur dioxide in-the high pressure evaporator H The sulphur dioxide liquefied in the heating system of the high pressure evaporator H is conveyed through a pipe F to a collecting vessel. Between the high pressure evaporator H and the evaporator V the pressure in which is equal to that of the vapours formed in the high pressure evaporator H are condensed in the heating system in the evaporator V while the sulphur dioxide vapours ,forn'1ed in the evaporator V from'the solution flow to the condenser C, where they are liquefied by the action due to the temperature of the cooling water. From the evaporator V the solution, which is by this time freed from the greater part of the sulphur dioxide, flows through a pipe containing a; regulating valve B into one or "in the arrangement shown in the drawing evaporator with a heating me from the outside (for instance, exhaust,

provision is made for heating Elbe subsequent steam).

The pipe systems which act both as condensers for the sulphurous acid vapours formed in one ofthe high pressure evaporators and as 'a means for heating the subsequent evaporator, may be located outside the evaporators and may for instance be constructed as double pipe apparatus, for instance in the manner of the condensers used in refrigerating plants.

One part of the sulphur dioxide vapours formed in the high pressure evaporators H,

H and so on may be made available for other heating purposes by being conveyed away through a branch pipe, for instance for evaporating the sulphurous acid dissolved in the refined product.

A further advantage obtained with the arrangement described besides the saving in heating is that the condenser C is smaller and that less cooling water is required. I

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1. -A process of recovering liquid sulphur dioxide from oils treated therewith which comprises heating a body of oil containing sulphur dioxide, said heating being under pressure, and condensing the evolved vapors of sulphur dioxide while inheat exchange relationship with another body of oil whereby the second body of oil is heated and the sulphur dioxide vapors are liquefied.

2. The process of recovering liquid sulphur dioxide from oils containing the same which comprises heating the oil under pressure to vaporize the sulphur dioxide, condensing the sulphur dioxide vapor while in heat exchange relationship with another body of oil under a pressure less than'that of the first mentioned body'of oil whereby the oil is heated and the sulphur dioxidevapors are liquefied,

passing the-evolved sulphur dioxide vapors from the second body of oil 'into heat exchange relationship with a third body of oil whereby the sulphur. dioxide vapors are liquefied and condensing the sulphur dioxide ium supplied 

